Infinitely large, definitely cryptic

This is an infinite cryptic crossword. Solve the clues and use the four given grid pieces (each duplicated infinity times) to create a grid that continues endlessly in all directions.

Across
A1. Soldier that earns pay from sea in Ajaccio, Corsica’s capital
A3. Crazed maniac? Her rant shows extreme depression (2 wds.)
A5. High frequency of broken heart during concert Zappa’s leading
A6. Birds almost turn home and escape, maybe
B3. One missing from couple? That’s standard
B5. Arguments for people getting paid
B6. Near stern judge (later president) William, Howard needs no introduction
B8. A tiny bird in action (2 wds.)
C1. Sending back gloomy music lover to a small island (2 wds.)
C2. "Dr. West?" – Looking towards West, Dr. King said he had one
C7. Fencing equipment is covered in the PE exam
D2. Shadow regularly covers edge of Bronx, New York state
D3. Whistleblower lost rank
D5. "Tatars possibly engaged in illegal activities" – article, NYT’s cover
D6. Explosive device backfiring in increased rate, perhaps

Down
A1. Muslims initially request face covering
A2. Flying cars in Australian city
A3. One thousand milk products served up? That’s a lot
A4. I moved to northernmost extreme in French territory to identify lizard
B1. Ultimately, Francis is not someone to be revered
B2. Harm evil entity with gas
B4. "The Living Daylights" – group of antagonists hunting agents’ heads (hyph.)
B7. Radical extremists in Zimbabwe supported by many
C3. The unstable Yankee left compound
C4. Just retired, actor Irons undressed
C5. Pause speech for recovery
C6. A stand-up storyteller from Greece
D1. Former lover, according to a friend of Barney Stinson’s, is upset
D2. Labourer and I escaped upcoming infernos
D4. Pianist Tatum’s music?